Rectifier



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, phide Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE CARLHAMBUECEEN, OF BELLEVILLE, ILLINOIS, ASSIGNOB TO THE B-L ELECTRICMANUFACTURING COMPANY, OF 8'1. LOUIS, MISSOURI, A CORPORATION OE MIS-SO'UBI momma No Drawing.

This invention relates to dry current recti- In the patent to PawlowskiNo. 834,924 there is described and claimed a rectifier for alternatingcurrent consisting of platesv or discs of electro positive metals andelectro negative metals arranged in contact with each other. Theasymmetric couples so formed depend for their action on the presence ofa rectifying or bonding "material between the electrode elements.Various methods for forming this rectifying or' bonding material havebeen proposed. In the Ruben Patent No. 1,649,741 the electro positiveelement is coated with a sulphide (or hydroxide) by placing it in a bathsulphide and connecting it as the anode in a current path through thesulphide solution to a suitable cathode electrode such as brass andnickel.

In my copending application Serial No. 440,635 filed March 31, 1930 Ihave disclosed and claimed a dry current rectifier in which the electronegative electrode element is provided with a bonding surface of aninorganic salt of an electro positive metal which bonding surface isarranged in contact with the electro positive electrode element.

I have found that an eflicient rectifier may be produced by arranging aplate or disc of an electro positive metal in contact with the surfaceof a sulphide of an electro negative metal having a surface layer of aniodide of an electro negative metal. In carrying out my invention Iprovide alternate discs or washers of aluminum or other electro positivemetal. These discs are assembled with the-discs of copper sulphidetreated in the manner described above and a rectifying unit of anynumber of cells may be constructed in the usual manner by assembling thealternatediscs on a bolt or other support between suitable end platesand suitable connecting plates in the usual manner. The coppersulwashers are prepared by heating copper washers in the presence ofsulphur to a temperature at which reaction betweenthe two takes placeand the copper washers are converted to copper sulphide. The washersemployed in my rectifier are essentially cu- Application filed January2, 1931.

of an alkaline Serial N0. 506,313.

prous sulphide. When copper andsulphur react in the method set forthabove, the copper formed is a mixture of cuprous and cupric sulphidewith possibly some free sulphur present, but I have found by analysisthat there is a far greater proportion of cuprous present and that thewashers are thus essentially cuprous sulphide. To form cupric sulhide orwashers that are essentially cupric sulphide, it is necessary to useother methods than the mere heating of sulphur in the presence ofeachother. Although I prefer to employ cuprous sulphide washers, I mayalso employ washers tially cupric sulphide.

The surface of the copper which is to come in contact with the aluminumor other electro positive. electrode element is moistened with asolution of iodine dissolved in alcohol. The iodine reacts with thecopper sulphide to form a coating of copper iodide. The treated washers,each having a surface of copper iodide, are then assembled into arectifying unit with the copper iodide surface in contact with theelectro positive electrode elements and the assembly then tightenedunder a pressure of three hunand copper sulphide washer that are essenanalternating current by means of which the rectifier is formed. A furtherpressure of three thousand pounds is then applied to it and the unittightened under this pressure.

While a rectifier having the desired properties may be constructed bytreating the copper sulphide elements with iodine in the mannerdescribed above, I have found that better results are obtained by theaddition of magnesium oxide to the solution of iodine to be applied tothe surface of the copper sulphide washers. Apparently some magnesiumiodide is formed. When copper sulphide washers or discs are treated withthis solution, copper iodide and some magnesium iodide is formed on thesurface of the wash ers. The alcohol used as a solvent evaporates"leaving the copper sulphide washer with a tive metal, and a highpressure can be put on the rectifying unit producing a unit that isimmediately operative without forming. While it is not entirely clearwhat reaction takes place, it is probable that some magnesium oxide isformed by decomposition of the magnesium iodide between the electropositive element and the copper sulphide element. eration for some timethe surfaces are welded together and when separated from each other, thealuminum presents a crystal]inestructure.

In another method of forming the electro negative electrode element, thecopper washers are first sulphided in the manner set forth above. Thecoating is prepared by mixing equal parts of finely ground coppersulphide, and iodine, and forming a solution in alcohol. As an example,10 grams of copper sulphide, finely ground, and 10 grams of iodine aredissolved in 50 cc. of alcohol. The iodine reacts with the coppersulphide to form cop,

per iodide. The copper sulphide changes to a grayish compound. Thesurfaces of the copper sulphide washers are then painted with thismixture and the alcohol permitted to evaporate. The treated coppersulphide washers are then assembled with electro positive electrodeelements, as described above, and produce a very efficient rectifier.

Instead of using an electro positive electrode element of aluminum,magnesium or other electro positive elements may be sub stitutedtherefor. Elements prepared in the manner outlined above may be used inany conventional rectifier construction and it is therefore believedunnecessary to illustrate or describe the rectifier in detail in thisspecification. The essential feature of the invention resides in thetreatment of the cop per sulphide electro negativeelements with asolution of iodine, or a solution of iodine to which magnesium oxide hasbeen added and the use of such treated electro negative elements inconjunction with electro positive elements of aluminum, magnesium orother electro positive metal with the electro positive electrode elementin contact with the treated surface of the electro negative element.

In the claims the term copper sulphide is intended to mean eithercuprous sulphide, cupric sulphide or a mixture of cuprous sulphide andcupric sulphide.

I claim:

1. A rectifying unit comprising an electro positive electrode element ofaluminum, an electro negative electrode element of copper sulphide, anda layer of copper iodide between said elements.

2. A rectifying unit comprising an electro positive electrode element ofa film forming metal, an electro negative electrode element of coppersulphide, and a layer of copper iodide between said elements.

After such rectifier has been in op The method of making dry currentrec-- tifiers which comprises applying a solution of iodine to thesurface of a copper sulphide 'electro negative electrode elements andassembling said copper sulphide electro ne ative electrode elements withelectro positive electrode elements with the treated surface of saidcopper sulphide electro negative electrode elements in contact with theelectro positive electrode elements.

4. The method of making dry current rectifiers which comprises addingmagnesium oxide to a solution of iodine, treating the surface of coppersulphide electro negative electrode elements with said solution, andassembling said treated copper sulphide electrode elements with electropositive electrode elements with the treated surface in contact with theelectro positive electrode elements.

A rectifying unit comprising an electro positive electrode element ofmagnesium, an electro negative electrode element of copper iisulphide,and a layer of copper iodide between said elements.

In testin'iony whereof I aflix my signature.

CARL HAMBUECHEN.

